Installers secure torsion springs to a metal shaft above
the garage door. Depending on the system, the shaft may pass through the middle
of the springs or spring, or the shaft may sometimes house the spring. If the
shaft passes through the middle of the torsion spring, the spring may be
mounted in the middle of the shaft or on the end of the shaft by the outside
edge of the garage door.

Torsion springs have three characteristics that determine
the lift and cycle life. These properties are the wire size, inside diameter
and length. The lift, which is determined by the torque of the spring, tells
how much weight the spring can lift. The cycle life tells how many times the
garage door should open and close before the spring breaks.

Standard Torsion Springs

Standard torsion springs lead as the most common torsion
springs in the garage door industry.

Residential garage doors typically utilize either one or
two springs. On a lighter garage door, one spring will suffice. In that case,
the torsion spring may be mounted to the spring anchor bracket in the middle of
the shaft above the garage door. Other times, the spring has an offset mount,
meaning that technicians do not mount the spring anchor bracket above the
center of the garage door.

If two torsion springs supply lift for the garage door,
they are typically mounted to the spring anchor bracket above the middle of the
garage door. Having two springs on the garage door tends to make it safer,
especially if one spring breaks when the door is open. The other spring will
then keep the garage door from falling and injuring a person or causing damage
to the garage door or other property.

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Extension springs install on the sides of the garage
door. A metal shaft does not run through the length of each spring. To provide
more safety, some door users supply a cable which runs through each of the
springs.

Most residential garage doors only have two extension
springs – one on each side of the door. Commercial doors, however, can have
multiple springs installed on each side. Extension springs have either looped
ends or special clips in the end of the springs. This allows the spring to be
hooked and attached to a part that secures the spring to the door and to the
garage frame.

Sectional Garage Door Extension Springs

Sectional garage door extension springs are the most
common extension springs in the American garage door industry. These springs
stretch nearly horizontally over the tracks on each side of the door, running
parallel to the side of the opened garage door. The back end of the extension
spring connects to an open-eye bolt, which connects in turn to angle iron or
the garage frame. This spring uses a wire as a safety cable.Residential garages
almost always utilize two springs, one on each side of the door. One end of
each spring usually connects to an open-eye bolt. This bolt usually fastens to
the angle iron that holds to track or to a beam in the garage frame.

The other end of the extension spring connects to a
pulley with a pulley fork. A pulley typically attaches to the other end of the
extension spring with the help of a pulley fork. One end of the cable that goes
over this pulley is attached to a cable adjustment clip. An S-hook attaches to
this clip, as well as to the horizontal track. The other end of this cable
rolls over a second pulley and down to the bottom fixture on the bottom section
of the garage door.

While one end of the cable attaches to the bottom
fixture, the other end attaches to a cable clip. An S-hook secures this clip to
the track.